Agglomeration resin

Over the years, Dionex has developed a wide variety of latex agglomerated resins to meet various needs in IC. A review of these developments is given in a book by Weiss [16]. Properties of latex columns are summarized in Table 3.6. 

Table 5 Selected columns based on the latex-agglomerated resins.

In the post-dispersion process, the soHd phenoHc resin is added to a mixture of water, cosolvent, and dispersant at high shear mixing, possibly with heating. The cosolvent, frequently an alcohol or glycol ether, and heat soften the resin and permit small particles to form. On cooling, the resin particles, stabilized by dispersant and perhaps thickener, harden and resist settling and agglomeration. Both resole and novolak resins have been made by this process (25). 

For both suspension and mass polymerisations at less than 2% conversion, PVC precipitates from its monomer as stable primary particles, slightly below 1-p.m dia (4,10—12). These primary particles are stabilised by a negative chloride charge (4,13). Above 2% conversion, these primary particles agglomerate. Sectioning the PVC grains of either suspension or mass resins readily shows the skins primary particles at 1-p.m dia, and agglomerates of primary particles at 3—10-pm dia (4,7,8,14). 

Suspension Polymerization. Suspension polymerization is carried out in small droplets of monomer suspended in water. The monomer is first finely dispersed in water by vigorous agitation. Suspension stabiUzers act to minimize coalescence of droplets by forming a coating at the monomer—water interface. The hydrophobic—hydrophilic properties of the suspension stabiLizers ate key to resin properties and grain agglomeration (89). 

Genencor International Spezyme (600 IGlU/g) S. rubiginosus Purified GI adsorbed on an anion exchange resin consisting of DEAE-celMose agglomerated with polystyrene and Ti02. Antrim and Auterinen, 1986 3.9... 

Whether or not stable nuclei and mechanically trapped voids grow or redissolve depends on several factors. Growth may occur via diffusion of air or water vapor or by agglomeration with neighboring voids. Dissolution may occur if the changes in temperature and pressure cause an increase in solubility in the resin, as we shall see. 

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